Didn’t realize that, but I am still interested in whether or not a ‘DMCA notice’ can be used for the entire statute or just in removing duplicate copies of infringing content.
The DMCA notice process is specifically about copyright infringement. The circumvention prohibited by chapter 12, section 1201 is not included in the definition of copyright infringement provided in chapter 5, and chapter 12 defines its own set of remedies for violations (both civil and criminal). So it seems completely unjustified to use the formal DMCA notice process for this kind of complaint—there's no copyright infringement here, so there's no need for a takedown process that protects online providers from being liable for their users' infringing activities.
There are various notices with different rules, and it's somewhat dumbing it down to refer to a singular "DMCA notice", which generally here is used to refer to a copyright takedown request but has never actually really mean that.